Process control systems, whether distributed control system (DCS) or supervisory control and data acquisition (SCADA) systems, generally include one or more process controllers communicatively coupled to at least one host (e.g., an operator workstation) and to one or more process control devices (e.g., field devices) configured to communicate via analog, digital or combined analog/digital communication signals and/or protocols. Such process control systems are commonly used in chemical, pharmaceutical, pulp and paper manufacturing and petroleum processes. The field devices can comprise device controllers, valves, valve actuators or positioners, switches, transmitters (e.g., temperature, pressure, flow rate, or chemical composition sensors), performing functions within the process control system such as opening and/or closing valves and measuring process parameters. The process controller receives signals indicative of process measurements made by the field devices and/or other information pertaining to the field devices, uses this information to implement a control routine, and generates control signals over buses and/or other communication lines to the field devices to control the operation of the process control system.
Modern industrial automation control systems manage and process real-time and/or essentially real-time information in the form of point data. In such control systems, a “tag” represents a structural data element comprising point data associated with various components (such as physical device components) of the system. Quite often the tag will be to reference derived or calculated values in the system, specific operator entered values/commands/requests, data associated with control strategy logic, or other logical entities such as timers. The point data of selected tags are made accessible to other components, systems, applications and/or users in the control systems in various combinations.
Generally, point data is subject to frequent change and may be monitored and reported through various operations and functions. Non-point data relates to a broad category of information that contextualizes point data in a variety of ways. Non-point data may include descriptive and/or attribute information characterizing the point data, as well as, other information such as limits, and ranges. In conventional control systems, integral and flexible manipulation of tag-based point data and non-point data is restricted due to their inherent differences and properties.
Modern industrial automation control systems, whether they are distributed control system (DCS) or supervisory control and data acquisition (SCADA) systems, are needed to provide plant operators with view and control of processes by interfacing with a variety of automation controllers using a range of different industrial communication protocols. The lifecycle of the industrial automation control system includes design, implementation, acceptance testing (at factory and/or on site), commissioning, and then maintenance during the operating life of the control system.
Traditional execution of the engineering of the automation control system throughout this lifecycle involves automation engineers programming a control strategy that is executed in an electronic automation controller (e.g. a programmable logic controller (PLC) or remote terminal unit (RTU)). Each register, or interfacing data point, or a collection of such data points, is then separately configured in the DCS or SCADA system as a ‘point’ in the automation system. Points fall into two major categories based on data type. Analog points are characterized by having real values that can be represented by the IEEE floating point numerical format. Status points are characterized by having discrete values in at least two states, the two sates being represented by a zero or a one. For accurate information to be presented to the user of the automation control system it is necessary that attributes of the point configuration such as the address for the value being acquired, the engineering units for the value and its range or state descriptors, are aligned with those assumed and configured in the control strategy being used in the automation controller. Being aligned is not necessarily exactly the same, as there may be some subtle syntax translations required, particularly for addressing where the syntax of the address in the automation controller may be slightly different from the syntax that is used in the automation control system.
During the life cycle of the automation control system, when alterations are made to the control strategy in the automation controller, the alignment of the automation system point configuration with the control strategy (including modified, added or removed points) is often a manual and time consuming task. This task requires the identification of changes in the program, manual alignment of the automation system configuration, and then subsequent verification and testing of the associated change in the automation system configuration.